def zpartner(self): """ Property that returns the Z-partner of the given object if it exists, otherwise returns None. """ if self._mod == 12: zint = Z_PARTNERS.get(self.pcint, None) if zint: return self.copy(utils.fromint(zint)) else: return for each in self.each_card(): if each.icv == self.icv: if each.prime._unique_pcs != self.prime._unique_pcs: return self.copy(each)